All kinds of theories have been floated to explain the mysterious noise blamed for ailments akin to brain trauma at the American embassy in Cuba. Now two scientists have put forth the simplest theory of all: crickets. More specifically, the scientists say they believe a certain cricket—the Indies short-tailed cricket—is responsible for the noise heard in this AP recording that emerged last year, reports the Guardian. "There’s plenty of debate in the medical community over what, if any, physical damage there is to these individuals," Alexander Stubbs of the University of California, Berkeley, tells the New York Times. "I can say fairly definitively is that the AP-released recording is of a cricket, and we think we know what species it is." The researchers, however, say their study doesn't rule out the possibility that victims suffered some other kind of attack.
Stubbs and Fernando Montealegre-Zapata of the University of Lincoln in England compared the sound in the recording to audio samples of crickets and say they found a clear match, that of the male Indies cricket singing for a mate. "The call of this Caribbean species is about 7 kHz, and is delivered at an unusually high rate, which gives humans the sensation of a continuous sharp trill," says Montealegre-Zapata, who recalls collecting crickets as a kid and having to evict a loud-singing male from his room one night. "I am not surprised that this call could disturb people who are not familiar with insect sounds," he said. Other theories: spytech gone wrong, a "mass psychogenic event", and microwave weapons. (Whatever the source, doctors say they have found real inner-ear damage in victims.)